#VU63573 Race condition in Linux kernel - CVE-2021-28964

Vulnerability identifier: #VU63573

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-28964

CWE-ID: CWE-362

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a local user to perform a denial of service attack.

The vulnerability exists due to a race condition in the get_old_root() function in fs/btrfs/ctree.c component in the Linux kernel. A local user can exploit the race and perform a denial of service attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.11.8, 5.11.8

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External links
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dbcc7d57bffc0c8cac9dac11bec548597d59a6a5
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PTRNPQTZ4GVS46SZ4OBXY5YDOGVPSTGQ/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4VCKIOXCOZGXBEZMO5LGGV5MWCHO6FT3/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/T2S3I4SLRNRUQDOFYUS6IUAZMQNMPNLG/
https://security.netapp.com/advisory/ntap-20210430-0003/
https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html
https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.